Human tissue-resident peritoneal macrophages reveal resistance towards oxidative cell stress induced by non-invasive physical plasma.

In the context of multimodal treatments for abdominal cancer, including procedures such as cytoreductive surgery and intraperitoneal chemotherapy, recurrence rates remain high, and long-term survival benefits are uncertain due to post-operative complications. Notably, treatment-limiting side effects often arise from an uncontrolled activation of the immune system, particularly peritoneally localized macrophages, leading to massive cytokine secretion and phenotype changes. Exploring alternatives, an increasing number of studies investigated the potential of plasma-activated liquids (PAL) for adjuvant peritoneal cancer treatment, aiming to mitigate side effects, preserve healthy tissue, and reduce cytotoxicity towards non-cancer cells. To assess the non-toxicity of PAL, we isolated primary human macrophages from the peritoneum and subjected them to PAL exposure. Employing an extensive methodological spectrum, including flow cytometry, Raman microspectroscopy, and DigiWest protein analysis, we observed a pronounced resistance of macrophages towards PAL. This resistance was characterized by an upregulation of proliferation and anti-oxidative pathways, countering PAL-derived oxidative stress-induced cell death. The observed cellular effects of PAL treatment on human tissue-resident peritoneal macrophages unveil a potential avenue for PAL-derived immunomodulatory effects within the human peritoneal cavity. Our findings contribute to understanding the intricate interplay between PAL and macrophages, shedding light on the promising prospects for PAL in the adjuvant treatment of peritoneal cancer.

Development of a Supramolecular Hydrogel for Intraperitoneal Injections.

Local intraperitoneal drug administration is considered a challenging drug delivery route. The therapeutic efficiency is low, mainly due to rapid clearance of drugs. To increase the intraperitoneal retention time of specific drugs, a pH-sensitive supramolecular hydrogel that can act as a drug delivery vehicle is developed. To establish the optimal formulation of the hydrogel and to study its feasibility, safety, and tissue compatibility, in vitro, postmortem, and in vivo experiments are performed. In vitro tests reveal that a hydrogelator formulation with pH ≥ 9 results in a constant viscosity of 0.1 Pa·s. After administration postmortem, the hydrogel covers the parietal and visceral peritoneum with a thin, soft layer. In the subsequent in vivo experiments, 14 healthy rats are subjected to intraperitoneal injection with the hydrogel. Fourteen and 28 days after implantation, the animals are euthanized. Intraperitoneal exposure to the hydrogel is not resulted in significant weight loss or discomfort. Moreover, no macroscopic adverse effects or signs of organ damage are detected. In several intra-abdominal tissues, vacuolated macrophages are found indicating a physiological degradation of the synthetic hydrogel. This study demonstrates that the supramolecular hydrogel is safe for intraperitoneal application and that the hydrogel shows good tissue compatibility in rats.

Loss of B1 and marginal zone B cells during ovarian cancer.

Recent advances in immunotherapy have not addressed the challenge presented by ovarian cancer. Although the peritoneum is an "accessible" locus for this disease there has been limited characterization of the immunobiology therein. We investigated the ID8-C57BL/6J ovarian cancer model and found marked depletion of B1 cells from the ascites of the peritoneal cavity. There was also selective loss of the B1 and marginal zone B cell subsets from the spleen. Immunity to antigens that activate these subsets validated their loss rather than relocation. A marked influx of myeloid-derived suppressor cells correlated with B cell subset depletion. These observations are discussed in the context of the housekeeping burden placed on innate B cells during ovarian cancer and to foster consideration of B cell biology in therapeutic strategies to address this challenge.

Farnesol remodels the peritoneal cavity immune environment influencing Candida albicans pathogenesis during intra-abdominal infection.

Candida albicans is a lifelong member of the mycobiome causing mucosal candidiasis and life-threatening, systemic, and intra-abdominal disease in immunocompromised and transplant patients. Despite the clinical importance of intra-abdominal candidiasis with mortality rates between 40% and 70%, the contribution of fungal virulence factors and host immune responses to disease has not been extensively studied. Secretion of the quorum-sensing molecule, farnesol, acts as a virulence factor for C. albicans during systemic infection, while inducing local, protective innate immune responses in oral models of infection. Previously, we reported that farnesol recruits macrophages to the peritoneal cavity in mice, suggesting a role for farnesol in innate immune responses. Here, we expand on our initial findings, showing that farnesol profoundly alters the peritoneal cavity microenvironment promoting innate inflammation. Intra-peritoneal injection of farnesol stimulates rapid local death of resident peritoneal cells followed by recruitment of neutrophils and inflammatory macrophages into the peritoneal cavity and peritoneal mesothelium associated with an early increase in chemokines followed by proinflammatory cytokines. These rapid inflammatory responses to farnesol significantly increase morbidity and mortality of mice with intra-abdominal candidiasis associated with increased formation of peritoneal adhesions, despite similar rates of fungal clearance from the peritoneal cavity and retro-peritoneal organs. C. albicans ddp3Δ/ddp3Δ knockout and reconstituted strains recapitulate these findings. This indicates that farnesol may be detrimental to the host during intra-abdominal infections. Importantly, our results highlight a need to understand how C. albicans virulence factors modulate the host immune response within the peritoneum, an exceedingly common site of Candida infection.

Revisiting the Use of Normal Saline for Peritoneal Washing in Ovarian Cancer.

The omentum is the predominant site of ovarian cancer metastasis, but it is difficult to remove the omentum in its entirety. There is a critical need for effective approaches that minimize the risk of colonization of preserved omental tissues by occult cancer cells. Normal saline (0.9% sodium chloride) is commonly used to wash the peritoneal cavity during ovarian cancer surgery. The omentum has a prodigious ability to absorb fluid in the peritoneal cavity, but the impact of normal saline on the omentum is poorly understood. In this review article, we discuss why normal saline is not a biocompatible solution, drawing insights from clinical investigations of normal saline in fluid resuscitation and from the cytopathologic evaluation of peritoneal washings. We integrate these insights with the unique biology of the omentum and omental metastasis, highlighting the importance of considering the absorptive ability of the omentum when administering agents into the peritoneal cavity. Furthermore, we describe insights from preclinical studies regarding the mechanisms by which normal saline might render the omentum conducive for colonization by cancer cells. Importantly, we discuss the possibility that the risk of colonization of preserved omental tissues might be minimized by using balanced crystalloid solutions for peritoneal washing.

The peritoneal cancer index as a predictor of complete cytoreduction at primary and interval cytoreductive surgery in advanced ovarian cancer.

OBJECTIVE: The peritoneal cancer index quantitatively assesses cancer distribution and tumor burden in the peritoneal cavity. The aim of this study is to evaluate the association between the peritoneal cancer index and completeness of surgical cytoreduction for ovarian cancer and to identify a cut-off above which complete cytoreduction is unlikely. METHODS: This is a single-center prospective cohort observational study. A total of 100 consecutive patients who underwent ovarian cancer surgery were included. Peritoneal cancer index scores prior to and after surgery were calculated, and a cut-off value for incomplete cytoreduction was identified using a receiver operator characteristic (ROC) curve. Surgical complexity, blood loss, length of surgery, and complications were analyzed and associations with the peritoneal cancer index score were evaluated. RESULTS: The overall median peritoneal cancer index score was 9.5 (range 0-36). The median age of the patients was 61 years (range 24-85). The most common stage was III (13% stage II, 53% stage III, 34% stage IV) and the most common histologic sub-type was high-grade serous (76% high-grade serous, 8% low-grade serous, 5% clear cell, 4% serous borderline, 2% endometrioid, 2% adult granulosa cell, 2% adenocarcinoma, 1% carcinosarcoma). Complete cytoreduction was achieved in 82% of patients, with a median score of 9 (range 0-30). The remaining 18% had a median score of 28.5 (range 0-36). The best predictor of incomplete cytoreduction was the peritoneal cancer index score, with an area under the curve (AUC) of 0.928 (95% CI 0.85 to 1.00). ROC curve analysis determined a peritoneal cancer index cut-off score of 20. Major complications occurred in 15% of patients with peritoneal cancer index scores >20 and in 2.5% of patients with scores ≤20, which was statistically significant (p=0.014). CONCLUSIONS: In our study we found that a peritoneal cancer index score of ≤20 was associated with a high likelihood of complete cytoreduction. Incorporating the peritoneal cancer index into routine surgical practice and research may impact treatment plans.

Migration of the ventriculoperitoneal shunt into the thoracic cavity: A case report and pitfalls of the rib structure.

Background: Although ventriculoperitoneal shunting (VPS) is a universal treatment for hydrocephalus, it is generally well-known that the procedure often has complications. Shunt catheter migration is one such complication, but no reports of migration into the thoracic cavity are associated with the surgical technique. Herein, I present a case of thoracic cavity migration of a shunt catheter alongside anatomical pitfalls of the rib structure. Case Description: The patient was a 62-year-old male diagnosed with subarachnoid hemorrhage due to craniocervical junction arteriovenous fistula and underwent direct surgery to occlude the fistula. We performed VPS for secondary hydrocephalus 1 month later. During VPS, the peritoneal catheter was tunneled subcutaneously over the clavicle to pass from the head to the abdomen. Several months later, the peritoneal catheter had migrated from the peritoneal cavity to the thoracic cavity. A computed tomography scan showed that the peritoneal catheter tunneled subcutaneously over the clavicle, penetrated the thoracic wall through the intercostal space between ribs 1 and 2, and entered the thoracic cavity. Conclusion: When performing VPS, it is not enough to send the passer through the skin over the clavicle; it must also be tunneled subcutaneously over the ribs while confirming the position of the tip by touch.

Association of the Bacteria of the Vermiform Appendix and the Peritoneal Cavity with Complicated Acute Appendicitis in Children.

BACKGROUND: Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children. METHODS: Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis. RESULTS: Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis. CONCLUSIONS: Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention.

Equinococosis quística peritoneal diseminada en paciente con infección Por VIH: reporte de caso / Disseminated peritoneal cystic Echinococcosis in a patient with HIV: case report

RESUMEN La equinococosis quística es una infección zoonótica producida por la larva de Echinococcus granulosus que es capaz de invadir diversos órganos desde su ubicación en el intestino humano. En los casos de coinfección con el virus de la inmunodeficiencia humana (VIH), existe una diversidad de complicaciones condicionadas por la enfermedad inmunosupresora con pronóstico reservado. El objetivo de este reporte es describir un caso de equinococosis multiquística peritoneal en una paciente en tratamiento antiviral para VIH durante casi diez años, que recibió la combinación de albendazol más cirugía, con evolución favorable. Este reporte sería el primero en el Perú en una persona con inmunosupresión por VIH y equinococosis quística.

ABSTRACT Cystic echinococcosis is a zoonotic infection caused by the larva of Echinococcus granulosus, which is capable of invading several organs starting from the human intestine. There are several complications in cases of co-infection with the human immunodeficiency virus (HIV), which are conditioned by the immunosuppressive disease and have poor prognosis. This report aims to describe a case of multi-cystic peritoneal echinococcosis in a patient under antiviral treatment for HIV for almost ten years, who received albendazole, underwent surgery and progressed favorably. This would be the first Peruvian report of a person with HIV and cystic echinococcosis.

Intraperitoneal metastasis of ovarian cancer: new insights on resident macrophages in the peritoneal cavity.

Ovarian cancer metastasis occurs primarily in the peritoneal cavity. Orchestration of cancer cells with various cell types, particularly macrophages, in the peritoneal cavity creates a metastasis-favorable environment. In the past decade, macrophage heterogeneities in different organs as well as their diverse roles in tumor settings have been an emerging field. This review highlights the unique microenvironment of the peritoneal cavity, consisting of the peritoneal fluid, peritoneum, and omentum, as well as their own resident macrophage populations. Contributions of resident macrophages in ovarian cancer metastasis are summarized; potential therapeutic strategies by targeting such cells are discussed. A better understanding of the immunological microenvironment in the peritoneal cavity will provide a stepping-stone to new strategies for developing macrophage-based therapies and is a key step toward the unattainable eradication of intraperitoneal metastasis of ovarian cancer.

Importancia del conocimiento anatómico del espacio extraperitoneal y su utilidad en los abordajes quirúrgicos / Importance of anatomical knowledge of the extraperitoneal space and its usefulness in surgical approaches

Introducción. El espacio extraperitoneal, se define como el segmento topográfico ubicado entre el peritoneo parietal internamente y la fascia transversalis externamente. Como resultado del desarrollo y consolidación de la cirugía laparoscópica, en particular de la herniorrafia inguinal por esta vía, se ha presentado un renovado y creciente interés en esta área anatómica, debido a la importancia de su conocimiento detallado en la cirugía de mínima invasión. Métodos. Se hizo una revisión narrativa de la literatura para presentar una información actualizada y detallada sobre la anatomía del espacio extraperitoneal y su importancia en diferentes procedimientos quirúrgicos realizados actualmente. Resultados. Por fuera del espacio peritoneal, se encuentran las áreas anatómicas externas al peritoneo parietal, que incluyen la preperitoneal y la retroperitoneal. Mediante la laparoscopia, se pueden localizar en estos espacios cinco triángulos anatómicos, además de la corona mortis y el triángulo supra vesical. Conclusión. El conocimiento del espacio extraperitoneal es de gran importancia para el cirujano general, teniendo en cuenta los múltiples procedimientos que requieren el abordaje de esta área topográfica

Introduction. The extraperitoneal space is defined as the topographic segment located between the parietal peritoneum internally and the fascia transversalis externally. As a result of the development and consolidation of laparoscopic surgery, particularly inguinal herniorrhaphy by this route, there has been a renewed and growing interest in this anatomical area, due to the importance of its detailed knowledge in minimally invasive surgery. Methods. A narrative review of the literature was made to present updated and detailed information on the anatomy of the extraperitoneal space and its importance in different surgical procedures currently performed. Results. Outside the peritoneal space are the anatomical areas external to the parietal peritoneum, including the preperitoneal and extraperitoneal. Using laparoscopy, five anatomical triangles, in addition to the corona mortis and the supravesical triangle, can be located in these spaces. Conclusion. Knowledge of the extraperitoneal space is of great importance for the general surgeon, taking into account the multiple procedures that require the approach of this topographic area

Reduction of peritoneal cavity B1a cells in adult Slc7a5 knockdown mice via dysregulating the mTOR pathway.

Slc7a5 is an important amino acid transporter that is highly expressed in metabolically active and rapidly proliferating cells. To explore the effect of Slc7a5 on adult B cell development, we conditionally deleted Slc7a5 in murine B cells and observed a significant reduction of B1a cells. In contrast to PI3K-Akt pathway activation, activity of the mTOR pathway was decreased. This may result from intracellular amino acid starvation in Slc7a5 knockdown (Slc7a5 KD) bone marrow B cells, thereby dampening B1a development. RNA-seq analysis demonstrated increased translation and reduced proliferation in Slc7a5 KD bone marrow B cells. Overall, the results of our study highlight the importance of Slc7a5 in peritoneal B1a cell development.

Expression of Gal-9 on Dendritic Cells and Soluble Forms of TIM-3/Gal-9 in Patients Suffering from Endometriosis.

Immune system dysregulation is clinically evident in the pathogenesis of endometriosis (EMS). Changes in the dendritic cells (DCs) activity or phenotype may be involved in the implantation and growth of endometrial tissue outside the uterus in the disease. The TIM-3/Gal-9 axis is implicated in the development of immune tolerance. However, the knowledge about the exact role of this pathway in the EMS is extremely poor. In the present study, we evaluated the expression of Gal-9 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 82) and healthy subjects (n = 10) via flow cytometry. We also investigated the concentrations of soluble Gal-9 and TIM-3 in the plasma and PF of EMS patients and the control group using ELISA. We showed significantly elevated percentages of mDCs-Gal-9+ and pDCs-Gal-9+, and significantly higher concentrations of the soluble form of Gal-9 and TIM-3 in the PF of EMS patients than in circulation. Our results led us to conclude that the accumulation of Gal-9 expressing mDCs and pDCs in the PF and high sTIM-3/Gal-9 production in the peritoneal cavity could represent the hallmark of immune regulation in EMS patients, which may augment the inflammatory process and development/maintenance of local immunosuppression.

Co-Treatment with Human Leukocyte Extract and Albendazole Stimulates Drug's Efficacy and Th1 Biased Immune Response in Mesocestoides vogae (Cestoda) Infection via Modulation of Transcription Factors, Macrophage Polarization, and Cytokine Profiles.

The model flatworm Mesocestoides vogae proliferating stage of infection elicits immunosuppression in the host. It was used to investigate the effects of human leukocyte extract (DLE) alone and in combination with anthelmintic albendazole (ABZ) on the reduction in peritoneal infection, peritoneal exudate cells (PECs), their adherent counterparts, and peritoneal exudates after the termination of therapy. Balb/c mice were infected with the larvae of M. vogae. PECs and adherent macrophages were studied via flow cytometry, mRNA transcript levels, and immunofluorescence. The cytokine levels were measured via ELISA and larvae were counted. ABZ significantly reduced larval counts (581.2 ± 65, p < 0.001), but the highest reduction was observed after combined treatment with ABZ and DLE (389.2 ± 119, p < 0.001) in comparison with the control. Compared to an infected group, the proportions of CD11b+CD19- myeloid cells with suppressive ability decreased after albendazole (ABZ) in combination with DLE, which was the most effective in the elevation of B cells and CD11b+F4/80mid/highMHCIIhigh macrophages/monocytes (22.2 ± 5.4%). Transcripts of the M2 macrophage markers (arginase 1, FIZZ-1, and Ym-1) were downregulated after DLE and combined therapy but not after ABZ, and the opposite trend was seen for iNOS. This contrasts with reduced ex vivo NO production by LPS-stimulated PECs from DLE and ABZ+DLE groups, where adherent macrophages/monocytes had elevated transcripts of the INF-γ receptor and STAT1 and reduced expression of STAT3, STAT6, and IL-10. Each therapy differentially modulated transcription profiles and concentrations of IFN-γ, TNF-α, IL-12p40, IL-6, IL-10, and TGF-ß cytokines. DLE strongly ameliorated ABZ-induced suppression of INF-γ and IL-12 and preserved downregulation for IL-4, IL-10, and TGF-ß. Epigenetic study on adherent macrophages from infected mice showed that ABZ, ABZ-sulfoxide, and DLE could interact with the mRNA of examined markers in a dose-dependent pattern. Co-administration of DLE with ABZ seemed to augment the drug's larvicidal effect via modulation of immunity. In comparison with ABZ, combined therapy was the most effective in alleviating parasite-induced Th2/Treg/STAT3/STA6 directed immunosuppression by stimulating the Th1 cytokines, M1 macrophage polarization, and activation of the IFNγ/STAT1 signaling pathway.

Mouse Tissue-Resident Peritoneal Macrophages in Homeostasis, Repair, Infection, and Tumor Metastasis.

Large peritoneal macrophages (LPMs) are long-lived, tissue-resident macrophages, formed during embryonic life, developmentally and functionally confined to the peritoneal cavity. LPMs provide the first line of defense against life-threatening pathologies of the peritoneal cavity, such as abdominal sepsis, peritoneal metastatic tumor growth, or peritoneal injuries caused by trauma, or abdominal surgery. Apart from their primary phagocytic function, reminiscent of primitive defense mechanisms sustained by coelomocytes in the coelomic cavity of invertebrates, LPMs fulfill an essential homeostatic function by achieving an efficient clearance of apoptotic, that is crucial for the maintenance of self-tolerance. Research performed over the last few years, in mice, has unveiled the mechanisms by which LPMs fulfill a crucial role in repairing peritoneal injuries and controlling microbial and parasitic infections, reflecting that the GATA6-driven LPM transcriptional program can be modulated by extracellular signals associated with pathological conditions. In contrast, recent experimental evidence supports that peritoneal tumors can subvert LPM metabolism and function, leading to the acquisition of a tumor-promoting potential. The remarkable functional plasticity of LPMs can be nevertheless exploited to revert tumor-induced LPM protumor potential, providing the basis for the development of novel immunotherapeutic approaches against peritoneal tumor metastasis based on macrophage reprogramming.

Diagnóstico, manejo y tratamiento de pacientes con peritonitis secundaria en una unidad de cirugía general / Diagnosis, management and treatment of patients with secondary peritonitis in a general surgery unit

La peritonitis es una inflamación aguda o crónica del peritoneo que generalmente tiene un origen infeccioso. Existen varios tipos, siendo la de tipo secundario la más frecuente. El término peritonitis secundaria se define como la inflamación localizada o generalizada de la membrana peritoneal causada por infección polimicrobiana posterior a la ruptura traumática o espontánea de una víscera o secundaria a la dehiscencia de anastomosis intestinales. Esta entidad se caracteriza por la presencia de pus en la cavidad peritoneal o de líquido; que, en el estudio microscópico directo, contiene leucocitos y bacterias. El tratamiento de esta patología constituye una urgencia y puede ser de tipo clínico y/o quirúrgico. El objetivo del manejo operatorio se basa en identificar y eliminar la causa de la infección, recoger muestras microbiológicas, realizar una limpieza peritoneal y prevenir la recidiva. El tratamiento clínico se ocupa de las consecuencias de la infección mediante la reanimación perioperatoria y el tratamiento antibiótico1. A pesar de los avances en diagnóstico, procedimientos quirúrgicos, terapia antimicrobiana y cuidados intensivos, la mortalidad asociada con la peritonitis secundaria grave es aún muy alta. El pronóstico y el manejo oportuno representan la clave para mejorar la sobrevida y reducir la mortalidad asociada a infecciones intraabdominales extensas2. Es importante establecer lineamientos en cuanto al diagnóstico, manejo antibiótico y pautas de tratamiento quirúrgico para disminuir la morbilidad y mortalidad asociada a esta enfermedad. Palabras clave: Peritonitis; Peritoneo; Cavidad Abdominal/cirugía; Cavidad Peritoneal; Líquido Ascítico/patología; Procedimientos Quirúrgicos Operativos.

Peritonitis is an acute or chronic inflammation of the peritoneum that generally has an infectious origin. There are several types, with secondary peritonitis being the most frequent. The term secondary peritonitis is defined as localized or generalized inflammation of the peritoneal membrane caused by polymicrobial infection following traumatic or spontaneous rupture of a viscus or secondary to dehiscence of intestinal anastomoses. This entity is characterized by the presence of pus in the peritoneal cavity or fluid which, on direct microscopic examination, contains leukocytes and bacteria. The treatment of this pathology constitutes an emergency and can be clinical and/or surgical. The aim of operative management is based on identifying and eliminating the cause of the infection, collecting microbiological samples, performing peritoneal cleansing and preventing recurrence. Clinical management deals with the consequences of the infection by perioperative resuscitation and antibiotic treatment1 . Despite advances in diagnosis, surgical procedures, antimicrobial therapy and intensive care, mortality associated with severe secondary peritonitis is still very high. Prognosis and timely management represent the key to improving survival and reducing mortality associated with extensive intra-abdominal infections2. It is important to establish guidelines for diagnosis, antibiotic management and surgical treatment guidelines to reduce the morbidity and mortality associated with this disease.

The Early Peritoneal Cavity Immune Response to Vibrio Anguillarum Infection and to Inactivated Bacterium in Olive Flounder (Paralichthys olivaceus).

The peritoneal cavity plays an important role in the immune response, and intraperitoneal administration is an ideal vaccination route in fish. However, immune responses in the peritoneal cavity of teleost fish are still not completely characterized. This study characterized the morphology of peritoneal cavity cells (PerC cells) and their composition in flounder (Paralichthys olivaceus). Flow cytometric analysis of the resident PerC cells revealed two populations varying in granularity and size. One population, approximately 15.43% ± 1.8%, was smaller with a lower granularity, designated as lymphocytes. The other population of the cells, about 78.17% ± 3.52%, was larger with higher granularity and was designated as myeloid cells. The results of cytochemical staining and transmission electron microscopy indicated that peritoneal cavity in flounder normally contains a resident population of leukocytes dominated by granulocytes, macrophages, dendritic cells, and lymphocytes. The percentages of IgM+, CD4+, G-CSFR+, MHCII+, and CD83+ leukocytes among PerC cells determined by flow cytometry were 3.13% ± 0.4%, 2.83% ± 0.53%, 21.12% ± 1.44%, 27.11% ± 3.30%, and 19.64% ± 0.31%, respectively. Further, the changes in IgM+, CD4+, G-CSFR+, MHCII+, and CD83+ leukocytes in flounder after Vibrio anguillarum infection and immunization were compared. The composition changed rapidly after the infection or vaccination treatment and included two stages, a non-specific stage dominated by phagocytes and a specific immune stage dominated by lymphocytes. Due to the virulence effectors of bacteria, the infected group exhibited a more intense and complicated PerC cells immune response than that of the immunization group. Following our previous study, this is the first report on the morphology and composition of PerC cells and the early activation of PerC cells in flounder response to V. anguillarum infection and vaccination.

Shunt Malfunction Without Device Occlusion: A Case Report.

Shunt malfunction is the most common cause of ventriculoperitoneal shunt failure. In literature, occlusion of the tube with brain parenchyma, choroid plexus, blood, and proteinaceous debris has been suggested as a mechanism of obstruction. We herein report a case of shunt malfunction without any identifiable occlusion. Our case findings suggest that unapparent abdominal pathology, including inflammation and fibrosis, should be considered when treating shunt failures.

Flow Cytometry Analysis of SIRT6 Expression in Peritoneal Macrophages.

The sirtuin 6 has emerged as a regulator of acute and chronic immune responses. Recent findings show that SIRT6 is necessary for mounting an active inflammatory response in macrophages. In vitro studies revealed that SIRT6 is stabilized in the cytoplasm to promote tumor necrosis factor (TNFα) secretion. Notably, SIRT6 also promotes TNFα secretion by resident peritoneal macrophages upon lipopolysaccharide (LPS) stimulation in vivo. Although many studies have investigated SIRT6 function in the immune response through different genetic and pharmacological approaches, direct measurements of in vivo SIRT6 expression in immune cells by flow cytometry have not yet been performed. Here, we describe a step-by-step protocol for peritoneal fluid extraction, isolation, and preparation of peritoneal cavity cells, intracellular SIRT6 staining, and flow cytometry analysis to measure SIRT6 levels in mice peritoneal macrophages. By providing a robust method to quantify SIRT6 levels in different populations of macrophages, this method will contribute to deepening our understanding of the role of SIRT6 in immunity, as well as in other cellular processes regulated by SIRT6. Graphical abstract.